CAMP Test Synergistic Hemolysis Guide
An original sheep blood agar bench diagram illustrating synergistic beta-hemolysis arrowheads for Group B Streptococci.
Bench card visual
CAMP reaction board
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Enhanced synergistic hemolysis occurs at the intersection of Group B Strep and beta-lysin producing S. aureus.
CAMP Hemolysis PlateStreptococcus agalactiae (A) vs Streptococcus pyogenes (B)
Streak A (GBS) shows complete arrowhead hemolysis. Streak B (GAS) shows no synergistic enhancement.
CAMP Hemolysis PlateStreptococcus agalactiae (A) vs Streptococcus pyogenes (B)
Streak A (GBS) shows complete arrowhead hemolysis. Streak B (GAS) shows no synergistic enhancement.
What to look for
| Visual clue | Meaning | Student shorthand |
|---|---|---|
| Arrowhead Hemolysis | Enhanced zone of complete lysis where GBS CAMP factor meets S. aureus beta-lysin | Shorthand: CAMP Positive (+) |
| Uniform Hemolysis | Standard narrow zone of beta-hemolysis without enhancement at the intersection | Shorthand: CAMP Negative (-) |
| Central Streak | Inoculation line of beta-lysin producing Staphylococcus aureus | Creates the baseline lysin gradient |
CAMP study readout
| Pattern | What to call it | How to think about it |
|---|---|---|
| Positive (+) | Clear arrowhead-shaped zone of complete lysis | Presumptive Streptococcus agalactiae (Group B strep) or Listeria monocytogenes (matchbox shape). |
| Negative (-) | No enhancement of lysis at the juncture | Presumptive Streptococcus pyogenes (Group A) or other beta-hemolytic streptococci. |
| Listeria variant | L. monocytogenes produces a block or matchbox shape | Used to confirm Listeria identification alongside tumbling motility. |
Key takeaways
- Presumptively identifies Streptococcus agalactiae (Group B streptococci).
- Group B strep is a leading cause of neonatal sepsis, meningitis, and pneumonia.
- PYR negative and CAMP positive confirms presumptive Group B strep status.
Remember
Group B strep is hippurate hydrolysis positive as well; use both tests for confirmation.